Draft mode generates FOP warnings

Hello,

I have a question around the draft mode.
Once activated, I do have the watermarked image on the generated PDF, 
but I also have a lot of warnings from FOP like:

[fop] WARNING: Line 1 of a paragraph overflows the available area. 
(fo:block, location: 2183/2412).

I tried to resize/scale draf.png but it did not removed the warnings. 
Does somebody knows how to solve this? Of course, removing the draft 
mode removes the warnings

Thanks and Regards,

Julien.
http://www.jujunie.com